1. Field of the Invention
The present invention relates to an improved light emitting diode, and particularly to a light emitting diode, which provides a base with a bottom part thereof free from sealing and exposing outside for a better heat dissipation.
2. Description of Related Art
A light emitting diode has been used as an effective light source for years. The light emitting diode provides advantages such as a longer life span, a higher lightness and lower power consumption such that it is widely applied in a signaling light, a brake light on a car, a Christmas decorative light, and etc. In addition, the light emitting diode can provide an effect of instant flash by way of circuit design as desired. Therefore, the light emitting diode is popularly used and there is a tendency for the light emitting diode to replace the conventional tungsten lamp.
As shown in FIG. 1, a typical light emitting diode provides at least two connecting pins xe2x80x9cAxe2x80x9d as a positive pole and a negative pole respectively. A base xe2x80x9cBxe2x80x9d is disposed above one of the poles at a lateral side thereof to receive a crystal chip xe2x80x9cCxe2x80x9d, and a brazed wire connects a nodal plate xe2x80x9cExe2x80x9d extended from the other pole to constitute a circuit. The above said pins xe2x80x9cAxe2x80x9d, base xe2x80x9cBxe2x80x9d, nodal plate xe2x80x9cExe2x80x9d are made of conductive sheet metal, and, in practice, are produced by way of integrally punch pressing a strip of conductive sheet metal.
As shown in FIG. 2, a blank sheet used for a prior art light emitting diode is illustrated. It can be seen that the blank sheet has been punch pressed to form a plurality of blank sections. Each blank section has connecting pins xe2x80x9cAxe2x80x9d, the base xe2x80x9cBxe2x80x9d, and the nodal plate xe2x80x9cExe2x80x9d, and the base xe2x80x9cBxe2x80x9d has a shape of concave inward cone. The rest unnecessary parts are cut out as removals.
As shown in FIG. 3, a bent blank is illustrated. Each connecting pin xe2x80x9cAxe2x80x9d in the respective blank section is bent into an angle of 90 degrees with respect to the base xe2x80x9cBxe2x80x9d and the nodal plate xe2x80x9cExe2x80x9d, and then the nodal plate xe2x80x9cExe2x80x9d and the chip xe2x80x9cCxe2x80x9d can be connected with each other via a brazed wire xe2x80x9cDxe2x80x9d.
In order to assure a protection for all parts related to the circuit, each blank section are insulated by way of sealing compound. As shown in FIG. 4, a hold fixture is provided with recessions to fit with pattern frames xe2x80x9cFxe2x80x9d. Each blank section is received in each pattern frame xe2x80x9cFxe2x80x9d and fits with the pattern frame such that the base xe2x80x9cBxe2x80x9d and the nodal plate xe2x80x9cExe2x80x9d are disposed in the pattern frame. Then, the transparent sealing compound such as epoxy resin is poured into each pattern frame xe2x80x9cFxe2x80x9d to be flush with the upper surface of the pattern frame xe2x80x9cFxe2x80x9d. When the poured sealing compound is solidified, the sealed blank sections are taken out and apart from the pattern frames xe2x80x9cFxe2x80x9d respectively. Finally, the sealed blank sections are separate into individual light emitting diodes and each of the light emitting diodes is like the one shown in FIG. 1. As shown in FIG. 1, the base xe2x80x9cBxe2x80x9d is completely covered by the sealing compound and insulated from the outside and the parts above the base xe2x80x9cBxe2x80x9d are in a state of being sealed to insulate from the outside either.
Once the light emitting diode is started in a state of on instantaneously, an instantaneous current consumption is great so as to generate a higher temperature in the light emitting diode. When the light emitting diode is kept xe2x80x9conxe2x80x9d for a long period of time, the heat generated from both of the chip and the wire solder is unable to release outward and results in a phenomenon of minor flaming. In this way, the durability of the light emitting diode may be influenced substantially.
In order to disclose a way overcoming the preceding defects in the prior art, the inventor has filed at the Chinese Patent Office and has been assigned Application No. 00107611.6 entitled xe2x80x9cLight Emitting Diode and Making Method with Blank Thereofxe2x80x9d. (The same invention also has been filed as a European Patent Application No. 00111453 and a U.S. patent application Ser. No. 09/583,236 respectively).
An object of the present invention is to provide an improved light emitting diode, with which the heat generated therein may transmitted through exposed connecting pins to ease the heat dissipation.